Pumping control system



Patented Oct. 31, 1950 UNITED STATES- PUMPING CONTROL SYSTEM Harrison B.Hoefcr, Milwaukee, Wis. Application July 14, 1944, Serial No. 544,949

5 Claims. .1

This invention relates to-controls for pumping systems particularly oflarge capacity such for instance as pumping systems for municipal water.works.

Large centrifugal pumps are today quite extensively employed in systemsof this type for supplying water against the substantial pressuresnormally maintained therein. The water from from the pump is ordinarilytransmitted through a large automatic valve that functions quitesatisfactorily under normal operating conditions. But this valve, asheretofore equipped, relies for operation upon the pressure and flowconditionsdeveloped by the pump and, in the event of pump failure,cannot be safely depended upon to check the resulting reverse flow orback surge with the promptness required to prevent serious consequences.

An object of the present invention is to provide a more positive controlfor the automatic valve in systems of this type so as to effect a morereliable operation thereof. This I have accomplished by a' controlarrangement for the valve involving an element mechanically connectedwith the pump and directly responsive to the speed of operation thereof.

Other more specific objects and advantages will appear, expressed orimplied, from the following description of an illustrative embodiment ofthe present invention.

In the accompanying drawings:

Figure 1 is a diagrammatic view of a control system embodying thepresent invention.

Fig. 2 is a sectional view on a larger scale of the governor controlledvalve and associated parts included in Fig. l.

The control system selected for illustration is shown applied to aconventional pumping system, including a large centrifugal pump III thatsupplies water through a large valve ll into a main I2. The valve II isa well known type of rotary valve, commercially known as a cone valve,which is actuated and controlled by an hydraulic servo-motor l3 withwhich such valves are commonly equipped. The piston I4 of theservo-motor is shown connected to the valve actuating lever l5 throughwhich the valve ll may be rotated into open. position from the closedposition shown.

In this instance the servo-motor I3 is controlled by, a four-way valvel6 which is actuated and controlled by a centrifugal governor I I drivenby the pump l through a one-way clutch I! of any standard or approvedtype. The servo-- motor l3 and consequently the valve II are renderedresponsive to the speed of the pump III, the arrangement being such thatthe valve II will promptly close whenever operation of the pump I0 fallsbelow a certain predetermined speed.

The centrifugal governor I! may assume vari- 55 the position shown.

ous forms. That shown comprises a supporting shaft I9 driven by theone-way clutch l8 and having thereon a pair of axially spaced end heads20 and 2|. Head 20 is fixed to the shaft l9 while head 2| is freelymovable axially thereof toward and fromthe-head 20. The heads carry asuitable centrifugal fly-ball arrangement which in this instancecomprises a pair of heavy bars 22 each connected to both heads throughflexible 10 metallic strips 23. The bars 22 are also interconnected by apair of parallel tension springs 24 disposed at opposite sides of theshaft l9, each end of each spring being connected to an end of a bar 22throughan appropriate link bolt 25.

The springs 24 yieldably resist outward movement of the bars 22 underthe centrifugal forces induced by rotation thereof with the shaft IS,in-

ward movement of the bars 22 being limited by suitable adjustable stops,such as screws 26 carried by a collar 21 on the shaft is.

The arrangement is such that during rotation of the shaft IS, the bars22 move outwardly and, acting through the strips 23,' draw the head 2|lengthwise of the shaft [9 a distance dependent 25 upon'the rate ofshaftrotation.

This axial movement of the head 2| is utilized to actuate and controlthe valve Hi. In this instance the valve I6 is equipped with an extendedvalve stem 28 that projects into the adjacent hol- 30 low end of theshaft IS. A transverse pin 28 carried by the head 2| and extendingthrough the stem 28 provides a suitable operating connectiontherebetween, the shaft I9 being longitudinally slotted to accommodatethe pin 23 and "to permit the same to move with the stem '28 and head2|.

The valve I6 is a four-way valve of a well known type. It includes alongitudinally movable plunger controlled by the stem 28 and hav- 40 mga central head 30. and spaced end heads 3| and 32. The central head 30controls an annular channel 33 that is continuously supplied with liquidunder pressure through a pipe 34. Each of the end heads 3| and 32controls an annular channel 35, both of which communicate with anexhaust pipe 36. An annular channel 31, disposed between the heads 30and 3|, conimunicates through a pipe 38 with one end of the servo-motor[3; while another annular channel disposed between the heads 30 and 32com- 00 is equipped with an actuating plunger 44 by which it may beopened in response to pressure generated by the pump [0. For thispurpose the plunger 44 is shown arranged within a cylinder 45 which isexposed to the discharge pressure of the pump l through apipe 4B. Thevalve 42 is preferably by-passed by a connection 41 containing asuitable check valve 48 arranged to permit a free flow of liquid throughthe pipe 40 in an opposite direction.

The arrangement is such that when the pump I0 is at rest the valve 42 isclosed and th lunger of the four-way valve It assumes the positionshown, in which position the forward end of the servo-motor I3 isexposed to the pressure in the supply pipe 34 through the channels 33and 31 and pipe 3!, and the cone valve II is held in closed position.When the pump i0 is energized gal governor ll, driven thereby, functionsto shift the plunger of the valve I8 toward the left (Fig. 2) until thecentral head 30 passes to the left of the supply channel 33, in whichposition the end head It uncovers the adjacent channel 35 so as to opencommunication between it and the channel 31 and the end head 32 blocksthe other channel 35. In this position the forward end of theservo-motor i3 is open to the discharge pipe 38 through the pipe 38 andchannels 31 and ll, and the pipe 40 is open to the supply pipe 34through the channels 39 and 33.

Although the four-way valve It has thus been operated in response to apredetermined speed of the pump ll in a manner to subject the pipe 40 tothe pressure in the supply pipe 34, the'servomotor l3 does not functionto open the cone valve ii until the pump 10 has generated apredetermined pressure suflicient to open the valve 42; but when thisoccurs, the pressure in pipe 40 is then available to promptly actuatethe servomotor It in a manner to open the valve II.

The valve Ii remains open so long as the speed of the pump in remainsabove a predetermined minimum, but with any decrease in speed, thegovernor ll forces the plunger of the valve, 14 toward the positionshown, and the instant that the and attains a predetermined speed, thecentrifupump speed falls below that minimum the central head 30 of thevalve I6 opens the supply channel 33 to the channel 37 to thereby directfluid pressure into the pipe 38 and to thus energlue the servo-motor I3in a direction to close the cone valve H. During this valve closingaction of the servo-motor, the liquid discharged therefrom is free toflow through the pipe 40 and check valve 48 to and through the valvchannels 3! and 35 to the exhaust pipe 35. It will be noted that thecheck valve 48 insures a free discharge of liquid from the servo-motorso as not to interfere with its valve closing action, even though thevalve 42 may have closed as a result of a drop in pump pressure.

A control system has thus been provided which functions to maintain themain valve ll open only while the pump I0 is functioning normally and ata speed above a. predetermined value and by which the valve H ispromptly closed whenever the pum speed falls below that value, so as toeffectively block the flow in the main i2 long before a reverse flow orback surge can develop therein as a result of pump failure. Should thepump in starting fail to develop alnormal pressure, as a result ofpriming failure or otherwise. the control system shown will function tohold the valve ll closed, the valve 42 being provided for that purpose.

It wfll be also noted that by reason of the fact that the governor I1 isdriven from the pump I 0 through a one-way clutch l8, the governor I!will come to rest or remain at rest, and consequently the valve 1 I willclose or remain closed, should the pump ill at any time operate inreverse.

Various changes may be made in the embodiment of the inventionhereinabove specifically described without departing from or sacrificingthe advantages of the invention as defined in the appended claims.

I claim:

1. In a pumping system the combination of a conduit, a pump forsupplying liquid to said con duit, a valve for controlling communicationbetween said pump and conduit, a servo-motor alternatively operable toopen and close said valve, and speed responsive ,means including acentrifugal governor driven by said pump and atomway valve actuated bysaid governor for rendering said servo-motor operable to open or toclose said valve whereby said valve is maintained in open condition onlywhen said pump is operating at speeds above a predetermined minimum.

2. In a pumping system the combination of a conduit, a pump forsupplying liquid to said conduit, a valve for controlling communicationbetween said pump and conduit, a servo-motor alternatively operable toopen and to close said valve, a four-way valve for controlling saidservomotor, and a centrifugal governor driven by said pump andmechanically connected to said last named valve to control the latter.

3. In a pumping system the combination of a conduit, a pump forsupplying liquid to said conduit, a valve for controlling communicationbetween said pump and conduit, a servo-motor alternatively operable toopen and to close said valve, a four-way valve for controlling saidservomotor, and a centrifugal governor driven by said pump and operableon said last named valve to actuate the same.

4. In a pumping system the combination of a conduit, a pump forsupplying liquid thereto, a

valve for controlling communication between said.

pump and conduit, a servo-motor alternatively operable to open and toclose said valve, means including a centrifugal governor for controllingsaid servo-motor, and a one-way clutch through which said governor isdriven by said pump.

5. In a pumping system the combination of a conduit, a pump forsupplying liquid to said conduit, a valve for controlling communicationbetween said pump and conduit, means including a centrifugal governorresponsive to the speed of said pump for opening said valve at apredetermined pump speed and for closing said valve at pump speeds belowsaid predetermined speed, and pressure responsive means for preventingopening of said valve when pump pressures are below a predeterminedminimum.

HARRISON B. HOEFER.

REFERENCES CITED The following references are of record in the die ofthis patent:

UNITED STATES PATENTS Number Name Date 868,541 Forester Oct. 15, 19071,123,876 Hiddleson Jan. 5, 1915 1,229,470 Joleen June 12, 19171,980,374 Bradshaw Nov. 13, 1934 2,067,479 Dahlstrand et al. Jan. 12,1937

